The House-Fly and Its Near Relations 



through the carriage and distribution of the germs of diseases of 

 the intestinal tract, such as typhoid fever and Asiatic cholera. 



Typical Life History 



{Musca domesiica.) 



This insect, known as the common house-fly, is found all 

 over the world. It lays its eggs by preference in horse manure 

 but in the absence 

 of this substance will 



oviposit and breed / ^jj^^ \ \ 



in other excrementi- C^M^^%J j 



tious matter and will 

 lay its eggs in decay- 

 ing vegetables, al- 

 though 1 have been 

 unable to rear it in 

 substances of the last 

 named character. It 

 is also difficult and 

 often impossible to 

 rear it from cow 

 dung. In horse manure, however, it flourishes. The eggs are 

 laid freely on horse manure in an undisturbed condition. These 



Fig. 94. — Morellia micans. {Author's illustration.) 



Fig. 95. — Stomoxys calcitrans. {Author's illustration.) 

 167 



